JP5204024B2 - Optical / wireless transmission equipment - Google Patents

Description

  The present invention relates to an optical / wireless transmission apparatus that wavelength-multiplexes a plurality of optical signals having respective optical frequencies on which transmission data is superimposed, optically / electrically converts the optical signals at each optical frequency, and transmits the transmission data as a radio signal. .

  The speed of optical access systems has been remarkably high, and in the last five years, the speed and bandwidth have increased by a factor of 100. Gigabit-class broadband services are now commercially available for GE-PON (Gigabit Ethernet (registered trademark)-Passive Optical Network) systems. Provided economically with introduction. Currently, next-generation PON technology for higher speed and wider bandwidth is also being studied.

  On the other hand, with regard to speeding up of the wireless access system, a wireless LAN exceeding 100 Mbps has been realized in the IEEE 802.11n standard, which will soon be standardized. In addition, the third generation mobile phone has already provided a High Speed Downlink Packet Access (HSDPA) service with a downlink of 7.2 Mbps, and is scheduled to provide a super 3G service exceeding 100 Mbps in 2010. As described above, in the next-generation wireless access system, there is an increasing expectation for realizing a gigabit-class high-speed service.

  Until now, wireless and wired (optical) technologies have been developed independently of each other. However, in order to realize future broadband and ubiquitous networks, flexible information communication that combines wireless and optical technologies. A system is essential. For this purpose, an optical transmission technique is required in which a radio signal is transmitted on an optical signal of an arbitrary optical frequency, transmitted through an optical fiber, optical / electrically converted, and transmitted as a radio signal.

FIG. 10 shows a configuration example of a conventional optical / wireless transmission apparatus (Non-Patent Document 1).
In the figure, CW light output from a light source 201 of an optical signal source 200 is input to an optical modulator 202, modulated by a 62.5 GHz sine wave signal 203, and converted to an optical frequency comb having an optical frequency interval of 62.5 GHz. Two CW lights whose optical frequencies are adjacent to each other are extracted from the optical frequency comb by the optical filter 204, combined, converted into CW light having an optical frequency interval of 125 GHz, and input to the optical modulator 210. The optical modulator 210 modulates CW light with an optical frequency interval of 125 GHz with transmission data (10 Gbit / s) and inputs it to an optical / electrical converter (O / E) 220 to generate a beat signal with a frequency of 125 GHz. It is transmitted as a radio signal with a frequency of 125 GHz. When the radio signal is received by the receiver 230, transmission data (10 Gbit / s) can be received.

  FIG. 11 shows a configuration example of a conventional optical / wireless transmission apparatus (Non-Patent Document 2). This configuration is an example in which RoF (Radio on Fiber) technology is applied to OADM.

  In the figure, light sources 302 having wavelengths λ1 to λn are directly modulated with RF signals 301 having different frequencies f1 to fn, respectively, and CW light is FM-modulated and input to an optical modulator 303. The optical modulator 303 outputs an optical modulation signal in which transmission data is superimposed on each CW light, and the WDM filter 304 multiplexes the optical modulation signals, FM / IM converts them by the Mach-Zehnder filter 305, and sends them to the OADM network. Each OADM node 306 selectively branches predetermined wavelengths λx and λy. The optical modulation signals of the wavelengths λx and λy are converted into electric signals by the light receiver 307, and a desired beat frequency is extracted by an electric filter (BPF) 308 from each beat signal of the RF frequency component subjected to IM conversion. Send as.

A.Hirata, et.al., "120-GHz-Band Millimeter-Wave Photonic Wireless Link for 10-Gb / s Data Transmission", IEEE Trans. Microwave Theory Tech., Vol.54, No.5, pp.1937 -1944, (2006) A.M.J.Koonen, et.al., "Perspectives of Radio over Fiber Technologies", OFC / NFOEC 2008, OThP3 (2008) M. Fujiwara, et.al., "Optical carrier supply module using flattened optical multicarrier generation based on sinusoidal amplitude and phase hybrid modulation", IEEE J. Lightwave Technol., Vol. 21, No. 11, pp.2705-2714, (2003)

  In a conventional optical wireless transmission device that combines wireless and light, a method has not been established for transmitting a plurality of transmission data as a wireless signal by superimposing a plurality of transmission data on an optical signal of a corresponding optical frequency and performing wavelength division multiplexing transmission.

  An object of the present invention is to provide an optical / wireless transmission apparatus capable of wavelength-multiplexing optical signals of a plurality of optical frequencies on which transmission data is superimposed and transmitting each transmission data as a radio signal with a simple configuration. And

The first invention is an optical frequency comb generator that outputs an optical frequency comb composed of CW light of a plurality of optical frequencies at an optical frequency interval f ₀ , and an optical frequency interval mf that is obtained by inputting the optical frequency comb and obtained by circularity. ₀ (m is an integer of 2 or more) CW light for each of a plurality of CW lights (n is an integer of 2 or more), and a plurality of CW lights having an optical frequency interval mf ₀ are transmitted. N optical modulators that respectively output the optical modulation signals modulated in step 1, a second optical filter that wavelength-multiplexes the optical modulation signals output from the n optical modulators, and wavelength-multiplexed transmission of the optical modulation signals An optical fiber transmission line, a third optical filter having the same demultiplexing characteristics as the first optical filter, and demultiplexing the wavelength-division-multiplexed optical modulation signal at an optical frequency interval mf _0; and an optical frequency interval Each of the optical modulation signals of mf ₀ is input, optical / electrical conversion is performed, and the optical frequency interval mf _{0 is obtained.} And n optical / electrical conversion means for converting the signal into an electric signal having a beat frequency corresponding to and transmitting as a radio signal.

According to a second aspect of the present invention, an optical frequency comb generator that outputs an optical frequency comb composed of CW light having a plurality of optical frequencies at an optical frequency interval f ₀ , and an optical frequency comb are input, and n (n is an integer of 2 or more) ) First CW light, a first optical filter that demultiplexes the first CW light and n second CW lights each having an optical frequency interval mf ₀ (m is an integer of 2 or more), N optical modulators that respectively output optical modulation signals obtained by modulating one CW light with transmission data, optical modulation signals output from the n optical modulators, and second optical CW light that is wavelength-multiplexed with the second CW light. 2 optical filters, an optical fiber transmission line for wavelength-multiplexed transmission of the optical modulation signal and the second CW light, and a wavelength-division-multiplexed optical modulation signal and the second CW light are demultiplexed every optical frequency interval mf ₀ A third optical filter, an optical modulation signal having an optical frequency interval mf ₀ and a second CW light are respectively input. And n optical / electrical conversion means for performing optical / electrical conversion to convert into an electrical signal having a beat frequency corresponding to the optical frequency interval mf ₀ and transmitting as a radio signal.

According to a third aspect of the present invention, an optical frequency comb generator that outputs an optical frequency comb composed of CW lights having a plurality of optical frequencies at an optical frequency interval f ₀ and an optical frequency comb are input, and (a + 1) (a is 2 or more) A first optical filter that demultiplexes into n (where n is an integer of 2 or more) CW light groups for each wavelength band including CW light, and an optical modulation signal obtained by modulating the CW light group with transmission data. N optical modulators that respectively output; a second optical filter that wavelength-multiplexes the optical modulation signals output from the n optical modulators; an optical fiber transmission line that wavelength-multiplexes the optical modulation signals; A third optical filter that has the same demultiplexing characteristics as the first optical filter and demultiplexes the wavelength-division-multiplexed optical modulation signal for each wavelength band; into an electric signal of the beat frequency corresponding to the optical frequency interval f ₀ ~af ₀ to electrical conversion, And n optical / electrical conversion means for transmitting an electric signal having one beat frequency as a radio signal.

The fourth invention is an optical frequency comb generator for outputting an optical frequency comb composed of CW light of a plurality of optical frequencies at an optical frequency interval f ₀ , and an optical frequency interval F obtained by inputting the optical frequency comb and obtained by circularity. _A first optical filter that demultiplexes into 0 (n is an integer of 2 or more) for each CW light group in a wavelength band including ₀ (a + 1) (a is an integer of 2 or more) CW light, and CW N optical modulators each outputting an optical modulation signal obtained by modulating an optical group with transmission data, a second optical filter for wavelength-multiplexing the optical modulation signals output from the n optical modulators, and an optical modulation signal And a first optical filter having the same demultiplexing characteristics and demultiplexing the wavelength-division-multiplexed optical modulation signal for each optical frequency interval F ₀ and for each wavelength band. of the optical filter, the optical frequency interval F ₀ a modulated optical signal of the wavelength band respectively input, / Electrically converted into an electric signal of the beat frequency corresponding to the optical frequency interval _{F 0 -af 0 ~F 0 + af} 0, n number of light / electricity transmitting the electrical signals of one of the beat frequency, respectively as a radio signal Conversion means.

According to a fifth aspect of the present invention, an optical frequency comb generator that outputs an optical frequency comb composed of CW lights having a plurality of optical frequencies at an optical frequency interval f ₀ and an optical frequency comb are input, and (a + 1) (a is 2 or more) N) (where n is an integer greater than or equal to 2) first CW light groups, and first CW light groups, and each of n second light beams having an optical frequency interval F ₀ . A first optical filter that demultiplexes the first CW light group, n optical modulators that output optical modulation signals obtained by modulating the first CW light group with transmission data, and outputs from the n optical modulators. The optical modulation signal, the second optical filter that wavelength-multiplexes the second CW light group, the optical fiber transmission line that wavelength-multiplexes the optical modulation signal and the second CW light group, and the wavelength multiplexed transmission A third optical filter that demultiplexes the optical modulation signal and the second CW light group for each optical frequency interval F ₀ and each wavelength band; , The optical frequency interval F ₀ in the wavelength band optical modulation signal and the second CW light groups respectively input, and optical / electrical conversion of the beat frequency corresponding to the optical frequency interval _{F 0 -af 0 ~F 0 + af} 0 N optical / electrical conversion means for converting into an electric signal and transmitting an electric signal of one beat frequency as a radio signal.

In the present invention, a plurality of CW lights having an optical frequency interval f ₀ or a plurality of CW lights having an optical frequency interval mf ₀ are extracted from the optical frequency comb, and the transmission data is superimposed on each of the CW lights to be wavelength-multiplexed and transmitted. The optical modulation signal corresponding to the CW light having the optical frequency interval f ₀ or mf ₀ can be optically / electrically converted, and the electric signal having the beat frequency can be transmitted as a radio signal. In this way, by performing wavelength division multiplexing transmission of a plurality of transmission data with optical signals of corresponding optical frequencies, transmission loss can be minimized and transmission quality of a radio signal to be transmitted can be improved.

It is a figure which shows the structural example of Example 1 of this invention. It is a figure which shows the structural example of Example 2 of this invention. It is a figure which shows the structural example of Example 3 of this invention. It is a figure which shows the structural example of Example 4 of this invention. It is a figure which shows the structural example of Example 5 of this invention. It is a figure which shows the structural example of Example 6 of this invention. It is a figure which shows the structural example of Example 7 of this invention. It is a figure which shows the structural example of Example 8 of this invention. 2 is a diagram illustrating a configuration example of an optical frequency comb generator 11. FIG. It is a figure which shows the structural example of the conventional optical / wireless transmission apparatus. It is a figure which shows the structural example of the conventional optical / wireless transmission apparatus.

FIG. 1 shows a first embodiment of the present invention.
In the figure, an optical frequency comb P0 composed of a plurality of optical frequency CW lights output from the optical frequency comb generator 11 is input to an optical filter (AWG) 12, and adjacent to each output port of the AWG 12 is the optical frequency comb P0. CW light having two optical frequencies is demultiplexed. Here, the optical frequency interval of the optical frequency comb is taken as f _0, the output port #i of AWG12 2 single CW light Pi of the optical frequency interval f ₀ is outputted (i is an integer of 1 to n, n is an integer of 2 or more).

The CW lights P1 to Pn demultiplexed by the AWG 12 are respectively input to the optical modulators 13-1 to 13-n, modulated by the transmission data 1 to n, and converted into optical modulation signals P1 ′ to Pn ′. The optical modulation signals P1 'to Pn' are combined by an optical filter (AWG) 14, wavelength-division-multiplexed via an optical fiber transmission line 15, and input to the optical filter (AWG) 16 to enter the optical modulation signals P1 'to Pn. And are input to optical / electrical converters (O / E) 17-1 to 17-n, respectively. The optical modulation signal Pi ′ input to the O / E 17-i is two optical modulation signals with an optical frequency interval f ₀ , and an electrical signal with a beat frequency f ₀ is generated by O / E conversion, and f ₀ is a radio frequency. Is transmitted as a radio signal Ri. In the figure, the configuration of the wireless signal transmission unit is omitted. The radio frequencies of the radio signals R1 to Rn are f ₀ corresponding to the optical frequency interval to be demultiplexed to the output ports of the AWGs 12, 14, and 16, and are all common.

The AWGs 12, 14, and 16 in the first embodiment have the same multiplexing / demultiplexing characteristics for performing the above-described multiplexing / demultiplexing, but the AWGs 12 and 16 can realize the same function with an optical coupler and n individual optical filters. Yes, the AWG 14 can realize the same function with an optical coupler.
In the first embodiment, the AWG 12 has a characteristic of demultiplexing two CW lights having two optical frequencies adjacent to one output port. However, the two CW lights demultiplexed to the two output ports are multiplexed. It is good also as a structure input into one optical modulator. In this case, the two CW lights may not be adjacent optical frequencies of the optical frequency comb. The AWG 16 is the same, and a configuration similar to that of the AWG 12 may be used by using one having the same demultiplexing characteristics.

FIG. 2 shows a second embodiment of the present invention.
In the figure, an optical frequency comb P0 composed of CW light of a plurality of optical frequencies output from the optical frequency comb generator 11 is input to the AWG 12, and each of the output ports of the AWG 12 has a plurality of optical frequencies at predetermined optical frequency intervals. CW light is demultiplexed. Here, when the optical frequency interval of the optical frequency comb is f ₀ , and the optical frequency interval (FSR) obtained by the circularity of the AWG 12 is mf ₀ , the output port #i of the AWG 12 has a plurality of optical frequency intervals mf ₀ . CW light Pi is output (m is an integer of 2 or more).

The CW lights P1 to Pn demultiplexed by the AWG 12 are respectively input to the optical modulators 13-1 to 13-n, modulated by the transmission data 1 to n, and converted into optical modulation signals P1 ′ to Pn ′. The optical modulation signals P 1 ′ to Pn ′ are combined by the AWG 14, wavelength-division-multiplexed via the optical fiber transmission line 15, and input to the AWG 16. The AWG 16 has an FSR of mf ₀ , and optical modulation signals P 1 ′ to Pn ′ having an optical frequency interval mf ₀ are demultiplexed at each output port and input to the O / Es 17-1 to 17 -n, respectively. O / E17-i input to the optical modulation signal Pi 'is a plurality of optical modulation signal of the optical frequency interval mf _0, the electric signal of the beat frequency mf ₀ is generated by the O / E conversion, the mf ₀ radiofrequency Is transmitted as a radio signal Ri. In the figure, the configuration of the wireless signal transmission unit is omitted. Further, the radio frequencies of the radio signals R1 to Rn are mf ₀ corresponding to the FSRs of the AWGs 12, 14, and 16, and are all common.

  The AWGs 12, 14, and 16 in the second embodiment have the same multiplexing / demultiplexing characteristics for performing the above-described multiplexing / demultiplexing, but the AWGs 12 and 16 can realize the same function with an optical coupler and n individual optical filters. Yes, the AWG 14 can realize the same function with an optical coupler.

FIG. 3 shows a third embodiment of the present invention.
In the figure, an optical frequency comb P0 composed of a plurality of optical frequency CW lights output from the optical frequency comb generator 11 is input to the AWG 12, and CW lights P1 to Pn having predetermined optical frequencies are respectively output to the output ports of the AWG 12. Pm + 1 to Pm + n are demultiplexed (n ≦ m). Here, when the optical frequency interval of the optical frequency comb is f ₀ , the CW lights Pi and Pm + i with the optical frequency interval mf ₀ are output to the output ports #i and # m + i of the AWG 12. The FSR of the AWG 12 is set to a value exceeding 2 mf ₀ .

The CW lights P1 to Pn demultiplexed by the AWG 12 are respectively input to the optical modulators 13-1 to 13-n, modulated by the transmission data 1 to n, and converted into optical modulation signals P1 ′ to Pn ′. The optical modulation signals P1 ′ to Pn ′ and the CW lights Pm + 1 to Pm + n demultiplexed by the AWG 12 are multiplexed by the AWG 14, wavelength-multiplexed via the optical fiber transmission line 15, and input to the AWG 16. The AWG 16 has an FSR of mf ₀ , and demultiplexes (P1 ′, Pm + 1) to (Pn ′, Pm + n) of the optical frequency interval mf ₀ to each output port, respectively O / E 17-1 to 17-. Input to n. O / E17-i optical modulation signal input to the Pi 'and CW light Pm + i of the optical frequency interval is mf _0, the electric signal of the beat frequency mf ₀ is generated by the O / E conversion, the mf ₀ radiofrequency Is transmitted as a radio signal Ri. In the figure, the configuration of the wireless signal transmission unit is omitted. The radio frequencies of the radio signals R1 to Rn are mf ₀ corresponding to the optical frequency interval between the output ports #i and # m + i of the AWGs 12 and 14 and the FSR of the AWG 16 and are all common.

  The AWGs 12 and 14 and the AWG 16 in the third embodiment have the multiplexing / demultiplexing characteristics for performing the above-described multiplexing / demultiplexing, but the AWG 12 and the AWG 16 can realize their functions with an optical coupler and n individual optical filters. Yes, the AWG 14 can realize the same function with an optical coupler.

FIG. 4 shows a fourth embodiment of the present invention. The fourth embodiment is a modification of the third embodiment.
In the figure, an optical frequency comb P0 composed of a plurality of optical frequency CW lights output from the optical frequency comb generator 11 is input to the AWG 12, and CW lights P1, P2, P2 having predetermined optical frequencies are respectively input to the output ports of the AWG 12. ..., Pi, Pi + 1, ..., Pn, Pn + 1 are demultiplexed (i and n are odd numbers). Here, when the optical frequency interval of the optical frequency comb is f ₀ , the CW light Pi, Pi + 1 with the optical frequency interval mf ₀ is output to the adjacent output ports #i, # i + 1 of the AWG 12.

The CW lights P1, P3,..., Pn demultiplexed by the AWG 12 are input to the optical modulators 13-1 to 13-n, respectively, and modulated by the transmission data 1 to n, respectively, and optical modulation signals P1 ′, P3 ′, ..., converted to Pn '. .., Pn ′ and the CW lights P2, P4,..., Pn + 1 demultiplexed by the AWG 12 are multiplexed by the AWG 14 and wavelength-multiplexed via the optical fiber transmission line 15. , Input to AWG16. The AWG 16 demultiplexes (P1 ′, P2) to (Pn ′, Pn + 1) of the optical frequency interval mf ₀ at each output port and inputs the demultiplexed signals to the O / Es 17-1 to 17-n, respectively. O / optical modulation signal input to the E17-i Pi 'and CW light Pi + 1 of the optical frequency interval is mf _0, the electric signal of the beat frequency mf ₀ is generated by the O / E conversion, the mf ₀ radiofrequency Is transmitted as a radio signal Ri. In the figure, the configuration of the wireless signal transmission unit is omitted. The radio frequency of the radio signals R1 to Rn is mf ₀ corresponding to the optical frequency interval between the adjacent output ports #i and # i + 1 of the AWGs 12 and 14 and the optical frequency interval demultiplexed to each output port of the AWG 16. All are common.

The AWGs 12 and 14 and the AWG 16 in the fourth embodiment each have a multiplexing / demultiplexing characteristic for performing the above-described multiplexing / demultiplexing. However, the AWG 12 and the AWG 16 can realize their functions with an optical coupler and n individual optical filters. Yes, the AWG 14 can realize the same function with an optical coupler.
In the fourth embodiment, the AWG 16 has a characteristic of demultiplexing the optical modulation signal and the CW light having the optical frequency interval mf ₀ to one output port, but the optical modulation signal and the CW light to be demultiplexed to the two output ports, respectively. May be combined and input to one O / E converter. In this case, the AWG 16 has the same demultiplexing characteristics as the AWG 12.

FIG. 5 shows a fifth embodiment of the present invention.
In the figure, an optical frequency comb P0 composed of a plurality of optical frequency CW lights output from the optical frequency comb generator 11 is input to the AWG 12, and (a + 1) (a is an integer of 2 or more) at each output port of the AWG 12. The CW light group in the wavelength band including the CW light is demultiplexed. Here, the optical frequency interval of the optical frequency comb is taken as f _0, the optical frequency interval f ₀ (a + 1) pieces of CW light group Pi is outputted at a predetermined wavelength band in the output port #i of AWG12 .

The CW light groups P1 to Pn demultiplexed by the AWG 12 are respectively input to the optical modulators 13-1 to 13-n, modulated by the transmission data 1 to n, and converted into optical modulation signals P1 ′ to Pn ′. . The optical modulation signals P1 'to Pn' are multiplexed by the AWG 14, wavelength division multiplexed through the optical fiber transmission line 15, input to the AWG 16, and demultiplexed into the optical modulation signals P1 'to Pn'. Input to converters (O / E) 17-1 to 17-n. The optical modulation signal Pi ′ input to the O / E 17-i is (a + 1) optical modulation signals with an optical frequency interval f ₀ , and electrical signals having beat frequencies f _{0 to} af ₀ are generated by O / E conversion. A predetermined beat frequency (here, af ₀ ) is selected via a band pass filter (BPF) 18-i and transmitted as a radio signal Ri having af ₀ as a radio frequency. In the figure, the configuration of the wireless signal transmission unit is omitted. The radio frequency of the radio signals R1 to Rn is any one of beat frequencies f _{0 to} af ₀ arbitrarily selected by the BFFs 18-1 to 18-n.

  Although the AWGs 12, 14, and 16 in the fifth embodiment have the same multiplexing / demultiplexing characteristics for performing the above multiplexing / demultiplexing, the AWGs 12 and 16 can realize the same function with an optical coupler and n individual optical filters. Yes, the AWG 14 can realize the same function with an optical coupler.

FIG. 6 shows a sixth embodiment of the present invention.
In the figure, an optical frequency comb P0 composed of a plurality of optical frequency CW lights output from the optical frequency comb generator 11 is input to the AWG 12, and (a + 1) pieces of light are output to each output port of the AWG 12 at predetermined optical frequency intervals. The CW light groups P1 to Pn in the wavelength band including the CW light are demultiplexed. Here, when the optical frequency interval of the optical frequency comb is f ₀ and the optical frequency interval (FSR) obtained by the circulatory property of the AWG 12 is F ₀ , the output port #i of the AWG 12 has a plurality of optical frequency intervals F ₀ . CW light group Pi is output.

The CW light groups P1 to Pn demultiplexed by the AWG 12 are respectively input to the optical modulators 13-1 to 13-n, modulated by the transmission data 1 to n, and converted into optical modulation signals P1 ′ to Pn ′. . The optical modulation signals P 1 ′ to Pn ′ are combined by the AWG 14, wavelength-division-multiplexed via the optical fiber transmission line 15, and input to the AWG 16. The AWG 16 has an FSR of F ₀ , and the optical modulation signals P 1 ′ to P n ′ with the optical frequency interval F ₀ are demultiplexed into the output ports and input to the O / Es 17-1 to 17 -n, respectively. Each of the optical modulation signals Pi ′ input to the O / E 17-i has (a + 1) optical frequency components and the optical frequency interval is F ₀ , and beat frequencies F ₀ −af ₀ to F by O / E conversion. An electrical signal of _{0 to} F ₀ + af ₀ is generated, a predetermined beat frequency (F ₀ + af _{0 in this case} ) is selected via a band pass filter (BPF) 18-i, and F ₀ + af ₀ is set as a radio frequency. It is transmitted as a radio signal Ri. In the figure, the configuration of the wireless signal transmission unit is omitted. The radio frequency of the radio signals R1 to Rn is any one of beat frequencies F ₀ −af _{0 to} F _{0 to} F ₀ + af ₀ arbitrarily selected by the BFFs 18-1 to 18-n.

  Although the AWGs 12, 14, and 16 in the sixth embodiment have the same multiplexing / demultiplexing characteristics for performing the above multiplexing / demultiplexing, the AWGs 12 and 16 can realize the same function with an optical coupler and n individual optical filters. Yes, the AWG 14 can realize the same function with an optical coupler.

FIG. 7 shows a seventh embodiment of the present invention.
In the figure, an optical frequency comb P0 composed of a plurality of optical frequency CW lights output from the optical frequency comb generator 11 is input to the AWG 12, and each of the output ports of the AWG 12 has a wavelength band including (a + 1) CW lights. The CW light groups P1 to Pn and the CW light groups Pm + 1 to Pm + n having the optical frequency interval F ₀ are further demultiplexed (n ≦ m). Here, the optical frequency interval of the optical frequency comb is taken as f _0, the output port # i of AWG12, CW light group Pi of the optical frequency spacing F _0, Pm + i is output to the # m + i. FSR of AWG12 is set to a value greater than 2F _0.

The CW light groups P1 to Pn demultiplexed by the AWG 12 are respectively input to the optical modulators 13-1 to 13-n, modulated by the transmission data 1 to n, and converted into optical modulation signals P1 ′ to Pn ′. . The optical modulation signals P1 ′ to Pn ′ and the CW light groups Pm + 1 to Pm + n demultiplexed by the AWG 12 are multiplexed by the AWG 14, wavelength-multiplexed via the optical fiber transmission line 15, and input to the AWG 16. The AWG 16 has an FSR of F ₀ , and demultiplexes (P1 ′, Pm + 1) to (Pn ′, Pm + n) of the optical frequency interval F ₀ to each output port, respectively O / E 17-1 to 17-. Input to n. The optical modulation signal Pi ′ and the CW light group Pm + i input to the O / E 17-i each have (a + 1) optical frequency components and the optical frequency interval is F ₀ , and the beat frequency is obtained by O / E conversion. An electric signal of F ₀ −af _{0 to} F _{0 to} F ₀ + af ₀ is generated, a predetermined beat frequency (F ₀ + af _{0 in this case} ) is selected via the band pass filter (BPF) 18 -i, and F ₀ It is transmitted as a radio signal Ri having a radio frequency of + af ₀ . In the figure, the configuration of the wireless signal transmission unit is omitted. The radio frequency of the radio signals R1 to Rn is any one of beat frequencies F ₀ −af _{0 to} F _{0 to} F ₀ + af ₀ arbitrarily selected by the BFFs 18-1 to 18-n.

  The AWGs 12 and 14 and the AWG 16 in the seventh embodiment have multiplexing / demultiplexing characteristics for performing the above-described multiplexing / demultiplexing, respectively. However, the AWG 12 and the AWG 16 can realize the respective functions with an optical coupler and n individual optical filters. Yes, the AWG 14 can realize the same function with an optical coupler.

FIG. 8 shows a seventh embodiment of the present invention. The eighth embodiment is a modification of the seventh embodiment.
In the figure, an optical frequency comb P0 composed of a plurality of optical frequency CW lights output from the optical frequency comb generator 11 is input to the AWG 12, and each of the output ports of the AWG 12 has a wavelength band including (a + 1) CW lights. CW light groups P1, P2,..., Pi, Pi + 1,..., Pn, Pn + 1 are demultiplexed (i and n are odd numbers). Here, when the optical frequency interval of the optical frequency comb is f ₀ , the CW light groups Pi, Pi + 1 with the optical frequency interval F ₀ are output to the adjacent output ports #i, # i + 1 of the AWG 12.

The CW light groups P1, P3,..., Pn demultiplexed by the AWG 12 are input to the optical modulators 13-1 to 13-n, respectively, and modulated by the transmission data 1 to n, respectively, and optically modulated signals P1 ′, P3 ′. ,..., Pn ′. .., Pn ′ and the CW light groups P2, P4,..., Pn + 1 demultiplexed by the AWG 12 are multiplexed by the AWG 14 and are wavelength-division-multiplexed via the optical fiber transmission line 15. And input to the AWG 16. The AWG 16 demultiplexes (P1 ′, P2) to (Pn ′, Pn + 1) of the optical frequency interval F ₀ to each output port and inputs the demultiplexed signals to the O / Es 17-1 to 17-n, respectively. The optical modulation signal Pi ′ and the CW light group Pi + 1 input to the O / E 17-i each have (a + 1) optical frequency components and the optical frequency interval is F ₀ , and the beat frequency is obtained by O / E conversion. An electric signal of F ₀ −af _{0 to} F _{0 to} F ₀ + af ₀ is generated, a predetermined beat frequency (F ₀ + af _{0 in this case} ) is selected via the band pass filter (BPF) 18 -i, and F ₀ It is transmitted as a radio signal Ri having a radio frequency of + af ₀ . In the figure, the configuration of the wireless signal transmission unit is omitted. The radio frequency of the radio signals R1 to Rn is any one of beat frequencies F ₀ −af _{0 to} F _{0 to} F ₀ + af ₀ arbitrarily selected by the BFFs 18-1 to 18-n.

The AWGs 12 and 14 and the AWG 16 in the eighth embodiment each have the multiplexing / demultiplexing characteristics for performing the above-described multiplexing / demultiplexing. However, the AWG 12 and the AWG 16 can realize their functions with an optical coupler and n individual optical filters. Yes, the AWG 14 can realize the same function with an optical coupler.
In the eighth embodiment, the AWG 16 has a characteristic of demultiplexing the optical modulation signal and the CW light having the optical frequency interval F ₀ to one output port. However, the optical modulation signal and the CW light demultiplexed to the two output ports, respectively. May be combined and input to one O / E converter. In this case, the AWG 16 has the same demultiplexing characteristics as the AWG 12.

A configuration example of the optical frequency comb generator 11 used in each of the embodiments described above is shown in FIG. 9 (Non-Patent Document 3).
In the figure, CW light having an optical frequency f output from a CW light source 111 is modulated by a sine wave signal 115 having a frequency f _{0 by} an optical intensity modulator 113 and an optical phase modulator 114, and light is transmitted to both sides of the optical frequency f. An optical frequency comb with a frequency interval f ₀ is generated. The configuration of the optical frequency comb generator shown here is an example. For example, a configuration using a phase modulator and a dispersion medium, etc., over a wide frequency range with an optical frequency interval f ₀ with respect to the optical frequency f of CW light. Any optical frequency comb having a flat spectral waveform with excellent SNR can be obtained.

  Moreover, in each Example demonstrated above, although the radio signal R1-Rn which transmits transmission data 1-n was superimposed on the optical signal of each optical frequency, the structure which carried out wavelength multiplexing transmission was shown, but as a transmission form, star type Either a bus type or a ring type configuration may be used. In addition, the transmission mode of the present invention can be similarly applied to a case where a single-system radio signal is transmitted point-to-point.

11 Optical frequency comb generator 12, 14, 16 Optical filter (AWG)
13 Optical Modulator 15 Optical Fiber Transmission Line 17 Optical / Electric Converter (O / E)
18 Bandpass filter (BPF)
111 CW light source 113 Light intensity modulator 114 Optical phase modulator 115 Sine wave signal

Claims (5)

An optical frequency comb generator that outputs an optical frequency comb composed of CW light of a plurality of optical frequencies at an optical frequency interval f ₀ ;
The first optical frequency comb is inputted and demultiplexed into n pieces (n is an integer of 2 or more) for each of a plurality of CW lights having an optical frequency interval mf ₀ (m is an integer of 2 or more) obtained by circularity. An optical filter;
N optical modulators each outputting an optical modulation signal obtained by modulating a plurality of CW lights of the optical frequency interval mf ₀ with transmission data;
A second optical filter that wavelength-multiplexes the optical modulation signals output from the n optical modulators;
An optical fiber transmission line for wavelength multiplexing transmission of the optical modulation signal;
A third optical filter having the same demultiplexing characteristics as the first optical filter and demultiplexing the wavelength-division-multiplexed optical modulation signal for each optical frequency interval mf ₀ ;
Each of the optical modulation signals having the optical frequency interval mf ₀ is input, optical / electrically converted to an electrical signal having a beat frequency corresponding to the optical frequency interval mf _0, and transmitted as a radio signal. An optical transmission device comprising: an electrical conversion means. An optical frequency comb generator that outputs an optical frequency comb composed of CW light of a plurality of optical frequencies at an optical frequency interval f ₀ ;
The optical frequency comb is input, and n (n is an integer of 2 or more) first CW light, and the first CW light, and n optical frequency intervals mf ₀ (m is an integer of 2 or more), respectively. A first optical filter that demultiplexes the second CW light;
N optical modulators each outputting an optical modulation signal obtained by modulating the first CW light with transmission data;
An optical modulation signal output from the n optical modulators, and a second optical filter that wavelength-multiplexes the second CW light;
An optical fiber transmission line for wavelength-multiplexing the optical modulation signal and the second CW light;
A third optical filter that demultiplexes the optical modulation signal and the second CW light that have been wavelength-multiplexed and transmitted at each optical frequency interval mf ₀ ;
The optical modulation signal and the second CW light having the optical frequency interval mf ₀ are respectively input, and optical / electrical conversion is performed to convert the optical signal into a beat frequency electrical signal corresponding to the optical frequency interval mf _0. An optical transmission device comprising: n optical / electrical conversion means for transmitting. An optical frequency comb generator that outputs an optical frequency comb composed of CW light of a plurality of optical frequencies at an optical frequency interval f ₀ ;
The optical frequency comb is input, and is demultiplexed into n (where n is an integer greater than or equal to 2) CW light groups for each wavelength band including (a + 1) (a is an integer greater than or equal to 2) CW light. An optical filter;
N optical modulators each outputting an optical modulation signal obtained by modulating the CW light group with transmission data;
A second optical filter that wavelength-multiplexes the optical modulation signals output from the n optical modulators;
An optical fiber transmission line for wavelength multiplexing transmission of the optical modulation signal;
A third optical filter having the same demultiplexing characteristics as the first optical filter, and demultiplexing the wavelength-division multiplexed optical modulation signal for each wavelength band;
Each of the optical modulation signals in the wavelength band is input, optical / electrically converted to be converted into an electric signal having a beat frequency corresponding to the optical frequency interval f _{0 to} af ₀ , and each electric signal having one beat frequency is a radio signal An optical transmission device comprising: n optical / electrical conversion means for transmitting as: An optical frequency comb generator that outputs an optical frequency comb composed of CW light of a plurality of optical frequencies at an optical frequency interval f ₀ ;
The optical frequency comb is inputted, and n (n is n) for each CW light group in a wavelength band including (a + 1) (a is an integer of 2 or more) CW light at an optical frequency interval F ₀ obtained by circularity. A first optical filter that demultiplexes into an integer equal to or greater than 2.
N optical modulators each outputting an optical modulation signal obtained by modulating the CW light group with transmission data;
A second optical filter that wavelength-multiplexes the optical modulation signals output from the n optical modulators;
An optical fiber transmission line for wavelength multiplexing transmission of the optical modulation signal;
A third optical filter having the same demultiplexing characteristics as the first optical filter, and demultiplexing the wavelength-division multiplexed optical modulation signal for each optical frequency interval F ₀ and each wavelength band;
Said optical modulation signal of the wavelength band in the optical frequency interval F ₀ respectively input, and optical / electrical conversion into an electric signal of the beat frequency corresponding to the optical frequency interval _{F 0 -af 0 ~F 0 + af} 0 An optical transmission device comprising: n optical / electrical converters each transmitting an electric signal having one beat frequency as a radio signal. An optical frequency comb generator that outputs an optical frequency comb composed of CW light of a plurality of optical frequencies at an optical frequency interval f ₀ ;
The optical frequency comb is inputted, and n (n is an integer of 2 or more) first CW light groups for each wavelength band including (a + 1) (a is an integer of 2 or more) CW light; A first optical filter that demultiplexes the CW light group into n second CW light groups each having an optical frequency interval F ₀ ;
N optical modulators each outputting an optical modulation signal obtained by modulating the first CW optical group with transmission data;
An optical modulation signal output from the n optical modulators, a second optical filter for wavelength multiplexing the second CW light group,
An optical fiber transmission line for wavelength-multiplexing the optical modulation signal and the second CW light group;
A third optical filter that demultiplexes the optical modulation signal and the second CW light group transmitted by wavelength division multiplexing for each optical frequency interval F ₀ and each wavelength band;
Said optical modulation signal and the second CW light group of the wavelength band in the optical frequency interval F ₀ respectively input, and optical / electrical conversion corresponds to the optical frequency interval _{F 0 -af 0 ~F 0 + af} 0 An optical transmission device comprising: n optical / electrical conversion means for converting into an electrical signal having a beat frequency and transmitting each electrical signal having one beat frequency as a radio signal.

Images